Automatic tube cleaner and catalyst injector



June 17, 1969 M. B. ALDRICH ET AL 3,450,104

AUTOMATIC TUBE CLEANER AND CATALYST INJECTOR Filed Dec. 4, 1967 Sheet of 5 June 17, 1969 M. B. ALDRICH ET AL 3,450,104

AUTOMATIC TUBE CLEANER AND CATALYST INJECTOR Filed DeC. 4, 1967 ECTOR AUTOMATIC TUBE CLEANER AND CATALYST INJ Sheet Filed Dec. 4, 1967 O m 4, w lllll M 3 8 4 {...i.:. a 2 4 l 9 4 3 u 5 u m 4 4 u 4 6 Mu v u n 4 3 lllll IL 5 u 7 n 4 I 5 5 5 9 e n 4 5 m O v M L 7 INVENTORI ATTORNEY M. B. ALDRICH ET AL 3,450,104 AUTOMATIC TUBE CLEANER AND CATALYST INJECTOR June 17, 1969 Filed Dec. 4, 19

June 17, 1969 M, ALDRlCH ETAL 3,450,104

AUTOMATIC TUBE CLEANER AND CATALYST INJECTOR Filed Dec. 4, 196? Sheet 5 of5 United States Patent U.S. Cl. 122-391 6 Claims ABSTRACT OF THE DISCLOSURE An apparatus for and method of keeping the tubes of a fire tube boiler clean and reducing the normal smoke and soot emissions developed by the combustion of the fuel, including soot blowing nozzles, means to introduce a catalyst into said tubes by said nozzles, and an automatic control for the device.

It has been known for many years that in fire tube boilers soot deposits accumulate in the tubes and other parts of the boiler and it has been the practice to provide manually operated soot blowers comprising nozzles to which steam or air under pressure may be supplied to blow the soot out of the tubes. This practice has been found to be helpful to increase the boiler efiiciency but efiiciency has remained discouragingly low, and the discharge of soot, carbon monoxide and sulphur dioxide to the atmosphere has remained high, and periodic shut-down of the boilers has been required to remove soot accumulations by hand.

It is an object, therefore, of the present invention to provide a device that will keep the tubes of a fire tube boiler clean, prolong tube metal life by preventing the buildup of sulphur and vanadium deposits and reduce the usual smoke and soot emissions resulting from the combustion of the fuel.

Other and further objects and advantages will become clear from the following specification taken with the accompanying drawing in which like reference characters of reference refer to similar parts in the several views and in which:

FIGURE 1 is an elevation of a fire tube boiler with the casing removed to disclose the tube sheet and fixed soot blowing nozzles;

FIGURE 2 is a fgragmentary section on line 22 of FIGURE 1;

FIGURE 3 is an enlarged view of the catalyst injector device as seen in FIGURE 1;

FIGURE 4 is a wiring diagram illustrating the means for operation of the soot blowers in a boiler similar to that of FIGURES 1 and 2;

FIGURE 5 is an elevation similar movable arm soot blower nozzles;

FIGURE 6 is a side view of one leg of the movable arm soot blower of FIGURE 5; and

FIGURE 7 is a wiring diagram showing the means for operation of the device of FIGURE 5.

In FIGURE 1 a tube sheet 10 of a fire tube boiler is provided with a plurality of fire tubes 11 extending, as illustrated, toward the fire box; that is, the products of combustion flow through tubes 11 toward the viewer. A compressed air header 12 provides air under pressure to a plurality of solenoid valves 13, 14, 15, and 16, each solenoid valve being connected by a pipe 17, 18, 19, and 20, respectively, to manifolds 21, 22, 23, and 24 leading to nozzles 25 of which one is provided opposite each tube 11. Each nozzle 25 is connected by a small diameter pipe 26 to one or other of the manifolds 21, 22, 23, and 24 so that each manifold, in this illustration, takes care of to FIGURE 1 using 3,450,104 Patented June 17, 1969 not less than a quarter of the tubes, to supply air to the tubes under high pressure. The number of tubes supplied by each manifold and the number of manifolds provided may, of course, be varied.

A further air connection 27 is provided with air from air header 12 leading to a solenoid valve 28, and thence to a device 29, to be described later, to introduce a catalyst into pipe 20 by way of a tube 30, shown as being connected to pipe 20.

To operate the device to perform the steps of the method, a control means indicated generally as a panel 31 is provided.

The steps of the method are, that when the boiler is ignited the control means receives power through a time delay switch upon operation of the burner solenoid valve (not shown) so remains inactive for a selected time. After the selected time delay the control is activated, by being connected to the power source via the time delay switch, thereafter at predetermined intervals air is provided to one of the manifolds 21, 22, 23, and 24 by activation of the corresponding solenoid valves 13, 14, 15, 16. So at these predetermined intervals a certain number of the tubes (in the illustrated installation a quarter of the tubes) are blown. If the selected interval is fifteen minutes, each bank of tubes in the device as illustrated in FIGURES l, 2, and 3, will be blown in each hour that the boiler burner is in operation. In the installation as illustrated a catalyst may be injected concurrently with blowing one bank of tubes. While provision may be made to supply catalyst when blowing other banks of tubes, the catalyst it is proposed to use (the formulation of which is not part of the present invention) does not require the more frequent introduction of catalyst.

When the burner of the furnace, or boiler, is not burning, that is, when the burner solenoid valve is closed, the control means 31 is disconnected from the power source and the operation of the system is suspended until the boiler or furnace burner is again ignited, and the predetermined time after ignition has elapsed. The tubes are only blown when the boiler, or furnace burner is in operation, and has been in operation for the predetermined time.

The control means as illustrated in FIGURE 4 is for use in a larger boiler having six banks of tubes.

When the coil of the oil burner solenoid valve 32 is energized and the toggle switch 33 of the tube cleaner control panel 31 is in the on position, current is furnished to the thermal element 34 of the time delay switch 35. After a thirty second interval (for instance) the time delay switch trips to closed position, the pilot light 36 then comes on, and the motor 37 of one-hour-multipleswitch-timer 38 is started.

After some minutes of operation the right hand cam 39 of the multiple switch timer trips the end timer switch 40 which energizes the motor 41 of the thirty second timer 42.

As the cams of the thirty second timer rotate the blow switch 43 is tripped for two short puffs and, at the end of ninety percent of revolution, the timer switch 44 reverses the circuitry and stops the operation of the thirty second timer.

At each fifteen minutes time interval one of the cams 45, 46, 47, 48, 49, 50, on the multiple switch timer switch 38 closes the microswitch pertaining to a corresponding air solenoid valve 51, 52, 53, 54, '55, 56 on its element 17, 1-8, 19, 20, etc. (see FIGURE 1) of the tube cleaner. During the time that each switch is closed the blow switch 43 energizes the air solenoid valve thru its own proper microswitch of the multiple switch timer. Each of the air solenoid valves then is blown consecutively at equal time intervals.

Before cata- Aitcr catalyst lyst but with still with tube cleaner tube cleaner Smoke scope (Ringelmann) 2 1 002 (percent). 8 10 (percent). 2. 5 1. 8

Stock temp. F. 260 252 Air velocity in breaching (IL/sec 18 18 C.i.m 2, 869 2, 867

P.p.m 1,080 503 Sulphur dioxide (4 tests) (percent) 4. 7 2. 1 Weight loss on 200 grams soot (grams or A similar system is shown in FIGURES 5 and 6. The boiler in FIGURE 5 is provided with a tube sheet 10a through which tubes 11a extend. Tube soot blowing nozzles 25a are mounted on manifolds 21a, 22a that are connected by a pipe 57 and a flexible hose 58 and pipe 59 to a solenoid valve 13a leading from an air header 12a. Manifolds 21a and 22a along with the connecting pipe 57 are movable across the face of tube sheet 10a, the arrangement of the tubes 11a in the tube sheet and the shape of manifolds 21a, 22a are such that for each position across the tube sheet, each nozzle 25a is aligned with a tube 11a.

The movement of the manifolds and nozzles is effected by sprocket and chain means 60 pulling the pipe 57 along supporting rails 61 (see FIGURE 6). The movement is controlled by a motor 62 that rotates a sprocket 63, seen in FIGURE 5.

The motor 62 is operated intermittently under the infiuence of a timer switch 64 seen in FIGURE 7 that is motor driven to close the switch at predetermined intervals and for predetermined times to move the manifolds 21a and 22a across the face of the boiler tube sheet. The motor of the timer switch 64 is not supplied with power until a predetermined time, perhaps thirty seconds after the solenoid valve 32a of the boiler burner has opened. The motor of timer switch 64 then operates continuously until the solenoid valve 32a again closes and it remains inactive until thirty seconds after the valve 32a has been opened again by operation of a thermostat or the like which is not a part of the present disclosure.

Whenever the solenoid valve 32a is receiving electric power, a transformer 65 is providing electricity at an appropriate voltage to operate the device. The transformer 65 may, of course, be omitted if the voltage requirement of the other elements agree with the voltage from the solenoid valve 32a.

When transformer 65 receives current the time delay switch 66 is provided with current so that this switch is closed after an appropriate time delay, and is held closed until the current from valve 32a is cut off by closing of the valve.

The timer motor for switch 64 is connected directly to one pole 67 of transformer 65 and is connected to the other pole 68 of the transformer 65 through the time delay switch 66. The switch 64 is cam operated: to close and provide motor 62 with power to move the manifolds 21a, 22a; and to open and stop the motor between the blowing of successive groups of tubes. When switch 64 is closed it also connects the blow switch 69 to the pole 68 of the transformer 65. When the blow switch is closed by a cam or motor 62 the timer motor of the switch 70 is activated and the tube blowing solenoid valve 13a is connected to the transformer so that these tubes are blown opposite which the manifolds 21a and 22a are at the moment. During the time that the valve 13a is thus activated, the timer motor for switch that activates the catalyst injector valve 28a will run. While it would be possible to have the timing for this switch 70 be such as to activate the catalyst injector each time any of the tubes are blown, it is desirable to have the timing of this switch be such as to provide catalyst at every third, fourth, or fifth actuation of valve 13a. If it is desired to inject catalyst at each blowing the switch 70 and its motor may be omitted.

A white light 71 is connected to show that the time delay switch 66 is closed. A red light 72 will flash each time the switch 69 closes.

The catalyst injector is seen in FIGURE 3, at 29. A catalyst container or hopper 73 is provided with an air tight removable cap 74 by which the device can be filled with powdered catalyst. At the bottom of hopper 73 a pipe 75 extends downwardly to an end 76 within pipe 77. The diameter of pipe 75 being large enough so that the catalyst will flow freely therethrough. One end of pipe 77 is connected at 78 with the solenoid valve 28, and the other end is connected at 79 with pipe 30 leading to the pipe 20 as described above in discussing FIG- URES 1 and 2. Connection 80 is provided to equalize the pressure in hopper 73 with that in pipe 77. Cut-off valve 81 is provided to facilitate filling hopper 73, by preventing inadvertent discharge of catalyst into the boiler room when filling the hopper.

Having thus disclosed our invention, we therefore claim:

1. A means to keep the tubes of a fire tube boiler clean under continuous operation, including a source of air under pressure, soot blower nozzles aligned with each fire tube, a plurality of manifolds, said nozzles being grouped in substantially equal numbers, and each group being connected to a corresponding manifold, solenoid operated valve means connecting each manifold to said source of air under pressure, and timing means to operate each said solenoid operated valve in succession at predetermined intervals.

2. The means of claim 1, including also a catalyst injector operatively connected to at least one said manifold to inject a catalyst into said boiler tubes when said one manifold is connected to said source of air under pressure.

3. The means of claim 1, in which said nozzles are positioned to blow into said fire tubes toward the fire in said boiler.

4. In a fire tube boiler, or the like, a fire box, a burner controlled by a solenoid valve, fire tubes extending from said firebox toward an uptake, a plurality of solenoid operated air valves, groups of soot blower nozzles each group connected to one of said solenoid valves, an air header connected to each said solenoid air valve to provide air under pressure thereto, a source of electric power connected to the solenoid of the solenoid controlled fuel valve for said burner, a time delay switch connected to receive electric power from said source of electric power when said solenoid switch for said fuel valve is actuated to open said fuel valve, an electric motor, a timer switch means driven by said electric motor, said electric motor being connected to said time delay switch so that it will be operated only after a time delay after opening of said fuel valve, said timer switch means including a plurality of switch means each connected to the solenoid of one of said solenoid operated air valves, said timer switch means being driven by said electric motor to close and open said switch means in sequence whereby each group of tubes will be blown in timed sequence.

5. A means to inject a soot and smoke reducing catalyst into an enclosed firebox burning zone or tube section comprising a source of air under pressure, a solenoid operated air valve connected to said source of air, a length of pipe, a hopper provided with an air-tight cover at the top and a discharge pipe at the bottom extending into said length of pipe, an air pressure equalizing connection between said length of pipe and a point near the top of said hopper, one end of said length of pipe being connected to said solenoid valve to receive air therefrom, and the other end of said length of pipe being connected to said fire box, and a timing switch connected to the solenoid of said air valve to provide for timed opening and closing of said air valve.

6. In a fire tube boiler, or the like, a fire box, a burner controlled 'by a solenoid valve, fire tubes extending from said firebox toward an uptake, a solenoid operated air valve, at least one group of movable soot blower nozzles connected to said solenoid valve, motor operated means to move said group of soot blower nozzles to selected positions in said boiler, an air header connected to said solenoid air valve to provide air under pressure thereto, a source of electric power connected to the solenoid of the solenoid controlled fuel valve for said burner, a time delay switch connected to receive electric power from said source of electric power when said solenoid switch for said fuel valve is actuated to open said fuel valve, a first electric motor to move said nozzles, and a second electric motor, a timer switch means driven by said second electric motor, said second electric motor being connected to said time delay switch so that it will be operated only after a time delay after opening of said fuel valve, said timer switch means including switch means connected to the solenoid of said solenoid operated air valve, said timer switch means being operative to periodically close and open said switch means whereby said group of movable nozzles will be moved to each selected position, and the tubes opposite that position each will be blown in timed sequence.

References Cited UNITED STATES PATENTS 2,163,489 6/1939 Hahn 122-391 1,675,725 7/1928 Petty 122-391 1,143,409 6/1915 Kyle 122-391 XR 2,620,632 12/1952 Rose 122-390 XR KENNETH W. SPRAGUE, Primary Examiner. 

